A number of authors have proposed image sensors with dense arrays of one-bit sensor elements (also referred to as “jots” or binary pixels). The pitch of the sensor elements in the array can be less than the optical diffraction limit. Such binary sensor arrays can be considered a digital emulation of silver halide photographic film. This idea has been recently implemented, for example, in the “Gigavision” camera developed at the Ecole Polytechnique Fédérale de Lausanne (Switzerland).
As another example, U.S. Patent Application Publication 2014/0054446, whose disclosure is incorporated herein by reference, describes an integrated-circuit image sensor that includes an array of pixel regions composed of binary pixel circuits. Each binary pixel circuit includes a binary amplifier having an input and an output. The binary amplifier generates a binary signal at the output in response to whether an input voltage at the input exceeds a switching threshold voltage level of the binary amplifier.